The present invention relates to an airtight adapter to be set to airtight units (including a vessel, equipment, or structure) and its replacing method.
As the airtight unit requiring airtightness, there are a device for handling, for example, nuclear fuel substance, radiation substance, toxic substance, chemicals causing a violent reaction, or specific bacteria or cell and a device for isolating water or a vacuum portion.
Particularly, to perform various tests or gene manipulations by bringing a nuclear fuel substance or radiation substance, toxic substance, chemicals causing a violent reaction, or specific bacteria or cell into the airtight units, it is necessary to strictly prevent the substance, bacteria, or cell from leaking or splashing to the outside.
As an airtight unit meeting the above requirements, a glove box, for example, is well known. FIG. 8 shows an example of the glove box.
In the case of the glove box 1, an operator observes the inside through an inspection window while bringing a test object such as a nuclear fuel substance or radiation substance inside and illuminating the object with previously-equipped various illumination means 2, 3 and 4, and performs predetermined tests by putting his hand into a retractable glove which is kept in an airtight state from the inside or by operating various testing equipments 5 with a robot hand.
The illumination means 2 uses, for example, a conventional fluorescent lamp. In this case, electric power is supplied to the means 2 from an external power supply 6 through an external cable 9a (electrical wire), an airtight adapter 40 disposed in the wall surface la of the glove box 1, and an internal cable 9b. Electric power is also supplied to the internal testing equipments 5 in the same manner. Moreover, control signals and data are transferred between the testing equipments 5 and an external unit 7 through an external cable 10a such as a signal line or optical cable and an internal cable 10b also provided through the airtight adapter 40.
Moreover, the illumination means 3 and 4 are used to directly take illumination light into the glove box 1 from an external light source 8 through a light guide (light transmission means) 11a. The illumination means 3 directly illuminates an object from the bottom end of the airtight adapter 40 disposed in the wall surface la of the glove box 1, while the illumination means 4 concentrically illuminates the hand of an operator by further connecting a light guide 11b constituted with a fiber bundle which can be freely moved to the bottom end of the airtight adapter 40.
The glove box 1 uses an airtight adapter 40 shown below. For example, the airtight adapter 40A shown in FIG. 9 is constituted by directly fixing a cylindrical adapter body portion 12 to the wall surface 1a of the glove box 1 through welding or the like, putting a glass rod (a transparent resin rod may be also used) 15a in the cylinder as light transmission means and also setting annular grooves 13 and 13 to two places at the inner surface of the cylinder, putting O-rings 14 and 14 in the grooves to keep airtightness, and connecting light guides 11a and 11b to the both ends of the glass rod 15a. In the case of the illumination means 3 of directly illuminating an object from the bottom end of the airtight adapter 40A, it is necessary to merely extend the glass rod 15a slightly into the glove box 1.
Moreover, another type of airtight adapter keeps airtightness by directly fixing the cylindrical adapter body portion 12 to the wall surface la of the glove box 1 through welding or the like, passing a cable such as a power supply line or signal line through the cylinder instead of the glass rod serving as the light transmission means in FIG. 9, and filling the cylinder with a filler such as a resin.
Still another type of airtight adapter is constituted with a cylindrical adapter body having a collar-shaped flange, and fixed to the wall surface 1a of the glove box 1 by a fixture such as a screw through the flange and moreover, a connection port connecting with the light guides 11a and 11b is formed on the inside of the both ends of the cylinder. Furthermore, the glass rod 15a contacting with the ends of the light guides 11a and 11b is inserted into the cylinder in an airtight manner through two O-rings 14 and 14 set to two annular grooves formed at the inner surface of the cylinder. Furthermore, an O-ring for sealing is positioned between the wall surface 1a and the flange.
Still another type of airtight adapter is constituted with a cylindrical adapter body having a collar-shaped flange, and fixed to the wall surface 1a of the glove box 1 by a fixture such as a screw through the flange and moreover, a cable such as a power supply line or signal line is passed through the inside of the both ends of the cylinder, and the cylinder is filled with a filler such as a resin to keep airtightness.
Furthermore, even in the case of an inspection window formed when the glove box 1 is made of an opaque material such as a metal, the inspection window is constituted with a type of airtight adapter structure. In this case, a sealing member such as a packing is fitted to the margin of a transparent body serving as a window glass, the member is brought into contact with the wall surface la of the glove box 1 together with a pressing frame and fitted to the opening of an inspection window portion of the glove box wall surface and the pressing frame is fixed by a fixture such as a screw.
However, the above airtight adapters have a problem that the initial light transmission characteristic cannot be obtained if an end face of the glass rod 15a is scratched when the light guides 11a and 11b are set or chemicals or chemical products are attached to the internal end face due to a chemical reaction in a glove box or splash of chemicals or chemical products under operation, because replacement of these adapters are not originally intended. Moreover, there is a problem that a filler through which a cable is passed or the cable itself is deteriorated as time passes due to a chemical reaction or splash of chemicals or chemical products in a glove box.
Particularly when cables are used, it is necessary to increase the number of cables or number of cable cores and correspond to the increase of cables or cable cores. Moreover, a transparent inspection window has a problem that it is contaminated or damaged as time passes.
In this case, because the above conventional airtight adapters are fixed-type and replacement of them is not intended as described above, it is impossible to correspond to the problems, the glove box itself may be disused, and therefore, the adapters are wasteful.